But instead of my signature being directly under the content, it was below both my linkwithin & sociable plugin stuff and above the tags/category meta info. How do I code it so that it goes directly at the end of my posts and above all the other stuff?

Good backups and knowing how to restore them are the best safety net you can have. Which I think you fully get 100%. 🙂

I think if you can put it back the way it was before this, then call it a night.

Don’t be discouraged, if you still want to work on your signature then as long as you make a copy of the file you are editing you really can’t cause too much harm. And recovering from something like this really is the best way to pick this all up.

It didn’t work. I added it via FTP but it won’t even show on my plugins page. Should I zip it first?

And no signature shows up on posts. I had to change the image extension to .PNG in the code because mine has a transparent background but I didn’t think that would mess anything up. I even added the image to my theme images golder as signature.PNG

No, that should have worked if the file was named shan-signature.php and the code was copied in, and that file was copied to wp-content/plugins…

I just tried it myself on my Crash Test Dummy. Centered image at the end of the post.

Can you check the permissions on that new file on your server? I’m not too familiar with FTP (industry thing, I never use FTP myself) but the file permissions should be something like rw-r--r-- for that new file.